High-speed camera



y 1953 F. w. HAYWARD ETAL 2,645,169

HIGH-SPEED CAMERA 2 Sheet's-Sheet 1 Filed Aug. 5, 1949 Z] YW wrvtou ,ywmd Zablockt muff, WHa v Uhaflles. J

July 14, 1953 F. w. HAYWARD ET AL 2,645,169

HIGH-SPEED CAMERA V Filed Aug. 5, 1949 v 2 Sheets-Sheet 2 frank Wjizyward C7zal'kas-JTZabl00kz? Patented July 14, 1953 HIGH- SPEED CAMERA Frank W. Hayward, Takoma Park, and Charles J.

Zablocki, Silver Spring, Md. I

Application August 5, 1949, Serial No. 108,832

3 laims. (01. 9517) (Granted under Title 35, U. S. Code (1952),

see. 266) The present invention relates to high speed cameras, and more particularly to improvements in rotatable drum cameras of the type dlSClOSGd in the copending application of Harry H. Hall for Method and Apparatus for High Speed Photography, Serial No. 692,157 filed August 22, 1946, now Patent No. 2,551,597, wherein a film strip is carried by the drum adjacent the periphery thereof.

In the aforesaid copending application, a high speed camera is disclosed in which a drum mounted for rotation within a casing is employed. The drum is constructed in such a manner as to retain a strip of film at the cylindrical periphery thereof whereby upon rotation of the drum at high speed past an optical opening in the casing of the camera the film will be constantly retained tangent to the focal plane of a lens positioned adjacent the optical opening and provided for focusing images to be photographed on the film.

A rotating drum type camera of the type disclosed in the copending application is Well adapted to photograph transient images such,- for example, as those appearing on the fluorescent screen of a cathode ray oscilloscope. It often is desirable to spread such transient images over a long time axis in order to bring out minute variations in the image and for this purpose the film on which the image is photographed is rotated at a high rate of speed such, for example, as 42 feet per second or higher.

In order to attain such high speeds without damage to the film and at the same time maintain the film precisely tangent to the focal plane of the lens, it has been found particularly advantageous to mount the film in a rotating drum.

In the Hall application heretofore referred to,

such a drum has been disclosed which comprises a cylindrical member composed of an inner and an outer annular member having a space provided therebetween for the insertion of a film strip. The inner annular member and the web provided for the support thereof are formed of metal, the inner annular member being provided with a slot for the insertion and removal of the film. The outer annular member is secured to the inner member and is formed of a transparent plastic material.

While the film carrying drum of the Hall application is generally well adapted for the purpose intended, several disadvantages have been discovered. In the first place, it has been found that it is particularly difficult to feed the film t r u h the slot of t e in er annular member into the space between the annular members. In addition to the difficulty in loading, there is also the possibility that the tab of film normally extending through the slot may be lost in the space between the annular members which would necessitate the disassembly of the two members. In the second place the prior art drum is expensive and difiicult to construct, it being constructed to a large extent of metal and, therefore, it must be accurately machined and because of its weight it must be delicately balanced in order to ensure smoothness of operation at high speeds.

In the device of the present invention the difficulties of the prior art device have been obviated to a great extent. The loading and removal of the film has been greatly facilitated by providing only one annular member having an open channel around the inner surface thereof, the side walls of the channel being cut back so that the film is snapped into place in the channel. The drum, including the aforesaid one annular member, is constructed of one piece of translucent plastic thereby eliminating the costly structural features of the prior art device, and being made of a single piece of lightweight plastic the necessity for delicate balancing is obviated.

It is also to be noted that the entire camera has been improved to provide a more compact a and efficient arrangement.

An object of the present invention is to provide a new and improved high speed camera having a rotating film retaining drum which is readily loaded and unloaded.

Another object is to provide a rotating drum for a high speed camera in which economical construction is an important feature.

Still another object is to provide a new and improved high speed camera which is readily attached to the enclosure ring of a cathode ray oscilloscope.

Still another object is to provide a new and improved high speed camera which is compact and neat in appearance.

A further object is to provide a rotating film retaining drum for a high speed camera which retains the film securely and tangent to the focal plane of the focusing lens.

A still further object is to provide a rotating film retaining drum composed of translucent plastic for a high speed camera which is light in weight and therefore capable of high speed rotation with a minimum of vibration.

Other objects and many of the attendant advantages of this invention will be readily appreciated as the same becomes better understood by reference to the following detailed description when considered in connection with the accompanying drawings wherein:

Fig. l is a side elevational view of a high speed camera and associated apparatus in which the device of the present invention may be employed;

Fig. 2 is a view in top plan of the camera and apparatus illustrated in Fig. 1;

Fig. 3 is a sectional view taken along the line 33 of Fig. 2; and

Fig. 4 is a sectional view taken along the line -l4 of Fig. 3.

Referring more particularly to the drawings wherein like numerals indicate like parts throughout the several views a high speed camera is indicated generally at H]. The camera it is arranged to record on a strip of film the movement of a cathode ray beam under the infiuence of an electronic circuit as employed in various test devices. In the present instance the camera it comprises a tubular body member Ii having a dual clamping member I2 at one end thereof. One portion of the clamp l2 engages the enclosure ring l3 mounted on the face panel of a cathode ray oscilloscope housing I4, While the other portion engages the body member H, as aforesaid.

The body member ii is mounted over a base plate 25 by means of a pair of brackets 55. Sup ported on body member ii is a casing ll of substantially circular formation and having a fiat wall H2 at one side thereof. The wall !8 is provided with a recess i9 jection 2i formed on the end wall of member ii. lhe foregoing arrangement is for the purpose of aligning the casing ll with respect to member 1 l.

Casin ii is releasably secured to member H by means of a finger 9 having an upturned end a to engage the flange of member H at the bottom and a fastener 22 at the top.

Formed within the casing ii is a cylindrical chamber 23 having communication with the camera casing Ii by means of a pair of apertures and 2 adjacent wall 98 of the casing.

An electric motor or other prime mover 25 is secured to one side of the casing II by means of screws or the like 25. An opening 2? is provided in the casing whereby shaft 2S of motor 25 may project interiorly of the casing. Fixedly secured to shaft 28 is a hub member 29 having a threaded shank 3i and a circular flange 32. Flange 32 has a pair of projecting pins mounted in the outer face thereof.

A transparent plastic drum 35 being of hollow cylindrical conformation and having one side closed by a wall 36 is arranged to be mounted on hub 29, a central orifice 33 being provided in wall 36 to receive the shank 3| of the hub and a pair of openings 37 being provided in the wall to receive the pins 34. A thumb nut screwed on shank 3i firmly secures the drum on the hub and pins B l prevent relative rotational movement of the drum and hub. Annular portion 38 of the drum is provided on the inner face thereof with a concentric channel 39 for receiving a strip of photographic film at, the edges of the channel being cut back at an angle of approximately 1 as at 42.

By referring to Figs. 3 and 4 it will be apparent that there has been provided a film carrying drum in which the film may be readily inserted or removed therefrom. It is also apparent that as the film is wider than the width of the outer adapted to receive a proportion of the channel of the drum, the film will be firmly held in the channel prior to the operation of the camera.

During rotation of the drum, the film will be held flat against the face of the channel through the action of centrifugal force, thus all of the film will be held concentric with relation to the axis of rotation of the drum.

As illustrated in Figs. 3 and 4, a shutter 43 is arranged in slot A l for closing the apertures 28 and 25. The shutter 43 may be operated by a solenoid d5 having a movable core 55 attached to one end of shutter 3. Solenoid it is secured in bore :26 in casing H by means of threaded plug 37. In order to return the shutter to the normal or closed position after movement to the open position under influence of the solenoid, a rod BS is attached to the opposite end of the shutter, the rod having a head -3:! adapted to ride in bore 5! and having a spring 5% interposed between the head and a shoulder 53 in the bore 5 i.

founted in projection 2i and extending into member it is a lens assembly The axes of (:lllll]. aperture 2! lens assembly and cathode tube mounted in housing i i are in parallel alignment. Thus, it wil be seen that, assuming that lens assembly properly focused, an image appearing on cathode ray tube will be clearly recorded on film G! as drum is rotated by motor 25 when shutter is is opened during one revolution of the drum.

Neon tube 55 is mounted within tubular mean-- ber ii and is connected in a flasher circuit (not shown) whereby the tube V. flash instants. ously at predetermined intervals measured fractions of a second as the shutter is open. The beam of li ht emanating from tube 55 is enclosed by an opaque shade 5G to prevent interference with the recording of the image of cathode ray tube 54.

Tube 5% is in alignment with aperture "it. Mounted in aperture 2 2 is a cylindrical lens 5? adapted to convert the beam of light from neon tube 55 to a narrow strip of light extending across the film ll. The foregoing arrangement is for the purpose of applying markings to the film to indicate periods of time.

An opening 58 is provided in the side of casing ii in order to permit access to the drum 35. The opening 58 is formed with a recess to provide for fiush mounting of a cover plate Fasteners E! are arranged to releasably secure the cover plate 59 to casing ll.

It is apparent from the foregoing description that the present invention provides a high speed camera which is compact and neat in appearance, and in which the film drum is c nstructed in a simple manner of a transparent plastic material and having features providing for easy loading and removal of the film.

Obviously many modification and variat he of the present invention are possible in the li ht of the above teachings. It is therefore to be understood that within the scope of the appended claims the invention may be practiced otherwise than as specifically described.

The invention described herein may be manufactured and used by or for the Government of the United States of America for governmental purposes without payment of any royalties thereon or therefor.

What is claimed and desired to be secured by Letters Patent of the United States is:

1. A high speed camera comprising a hollow cylindrical drum of a lightweight plastic material adapted to carry a film strip adjacent the periphery thereof, said drum comprising a circular Web, a translucent cylindrical member integral with the periphery of said web at one end of said cylindrical member, the inner surface of said translucent cylindrical member being provided with a shallow channel of width substantially the same as the width of said film strip, the side walls of said channel being undercut to provide means for anchoring said film strip in said channel, the inner surface of said cylindrical member providing support for said film strip over the entire area thereof whereby centrifugal force acting on said film strip upon rotation of said drum forces said film strip against the inner surface of said translucent cylindrical member, said hollow drum being open at one end thereof to permit access to the hollow interior thereof for insertion of said film strip in said channel.

2. In a high speed camera of the class disclosed, a translucent drum comprising a circular web, a transversely disposed flange formed along the entire periphery of said circular web and integrally therewith, a channel recessed within the inner surface of said flange of a width sufficient to receive a strip of film, the edges of said channel being undercut approximately 10 and in spaced relationship such that said film may be snapped over the undercut edges into the channel to a position in continuous surface contact with said flange.

3. In a high speed camera of the type disclosed, a translucent drum having a circular end 6 face and cylindrical wall portion integrally formed therewith, the other end of said drum being open, a channel formed in the inner surface of said cylindrical wall portion of a width sufiicient to receive a strip of film, the edges of said channel being undercut whereby a strip of V FRANK W. HAYWARD. CHARLES J. ZABLOCKI.

References Cited in the file of this patent UNITED STATES PATENTS Number Name Date 1,252,829 Mueller Jan. 8, 1918 1,536,716 Kade May 5, 1925 2,167,417 Chappell et al July 25, 1939 2,259,228 Rankin ct. 14, 1941 2,353,328 Winston July 11, 1944 2,372,774 Finch Apr. 3, 1945 2,394,225 Ashford Feb. 5, 1946 2,477,847 Zarem et a1. Aug. 2, 1949 2,505,469 Gerardin Apr. 25, 1950 2,551,597 Hall May 8, 1951 FOREIGN PATENTS Number Country Date 796,844 France Feb. 3, 1936 

